Exactly, 800 Nm, which is 590 lb-ft.
@FordTechOne Sir as always thank you. I respect your ethical, competent, consistent approach borne of experience in addressing us. If you have a moment—please let me know if I missed anything.
The engineer in me shakes my head every, single, time—when I hear of folks pushing more HP/TQ through OEM transmissions (at my company, at my previous employers, etc.).
The engineer in me shakes my head likewise when folks put larger diameter tires on a vehicle and then are puzzled when things go south at some point.
In my role the thermodynamics/fluids/metallurgy engineering background is necessary (military paid for every bit of my education including staying current in my ASME/AIAA membership for years while Active/NG—and I am forever thankful).
TRANSMISSION 101:
—Budget plays a role in design: If we wanted everything engineered perfectly, the Raptor would double in price easily. Engineering, procurement, etc., operates within a budget—and comes up with the best solutions possible.
—OEM: The nominal capacity of every drivetrain component (WARRANTY) is based on stock/factory parameters.
—TQ is extremely hard on transmissions, which is why nominal max is based on TQ—shifting places the TQ load on every component. TQ max hits the transmission 100% of the time for folks who accelerate through the gears.
—HP is hard on transmissions, but since it occurs at the top end of the rev range—the transmission is likely in the higher gears, which using my calculations on leverage/gearing is in a “sweeter spot” to deal with the power at the top end.
—Thermo/fluids physics: Energy creates heat, fluid motion creates heat, boundary transitions create heat, friction creates heat.
—Metals: Modern transmissions are a marvel of science. The engineered alloys w/resistance to heat & paradoxically may run cooler are placed in highest wear areas. This is a benefit as the strongest link needs to be the gears, bearings, etc., which withstand over 30 million shock stresses per minute (being conservative in this calculation as I based it on a 30 minute cycle and calculation we use at my company where the cycling from gear 1 to gear 5 is in city traffic, fluctuating from 0-50, based on proprietary calculations of how many stop starts occur).
—Clutch plates, etc: The metal information above is important as the strongest link as the transmission operates as a closed system. Friction absorbing clutch components are a weaker link which is good (high heat resistance, but wear faster than metal)
—Maintenance: Changing my transmission fluid/filter/and cleaning the internal components does nothing—does not help with the physics above. I could R&R the above daily—and it does not help with the physics (the living hell that clutch plates, gears, bearings, solenoids, etc. endure).
Nominal max TQ is most important for the reasons outlined above—which is why it is always posted. Nominal max HP is not posted/shared by OEMs in some cases (for various reasons which could create another engineering thread).
Bigger tires (37” vs. LT 305/70R-17fall far, far, outside of the design parameters for OEMs. Using math, the longer lever of a 37” tire
Heavier tires manufactured by reputable OEMs within reason, in stock OEM sizes (LT 305/70R-17) are well within design parameters—as the length of the lever does not change (the distance from hub to outside).
NOTE: This also impacts every, single, system in the drivetrain—engine/diffs/transfer case/CVs/u-joints/etc.)